my neighbor has an iphone 4s. It was working, now it's locked and he cannot unlock it.

when he tries to unlock it, there's a text to speech software software on iphone that speaks the digits he input, it even says "slide to unlock". But that's all, it doesn't unlock. I don't have an iphone so if anyone knows what is happening please tell me so i can help him, i don't know what my neighbor did to his phone either, he came to me saying what i just told you, that's all i know.
The text-to-speech is an accessibility feature called "VoiceOver". Your neighbor probably set a lock code on his phone. There is no way this would happen out of the blue. There isn't much he can do besides restoring the firmware.